WAN optimisers make bandwidth budgets go further

One of the surest ways for companies with expensive data links to save money is to install WAN acceleration devices. The gear pays for itself in as little as a few months, some users say.

The main way these devices save money is by making fixed-size links appear larger. This delays the need to buy more bandwidth.

WAN optimisers sit at both ends of connections and tune traffic so more of it crosses the wire more efficiently. The results are increased throughput, faster application response time and faster database access. A long list of vendors including Blue Coat, Expand Networks, F5 Networks, Juniper Networks, NetScaler, Orbital Data, Packeteer, Riverbed and Silver Peak make such appliances, which tap a range of technologies to achieve results.

These devices can have a quick ROI, for domestic links as well as international ones. For example, the payback for US financial services firm Susquehanna Bancshares was less than a year when it put Expand's WAN accelerators on a DS-3 connection between its Pennsylvania datacentres, which are 190km apart, says Rod Lefever, the firm's CTO.

The company used to outsource a disaster-recovery site where tapes would be shipped, replicated and brought online if the primary datacentre failed, but it was a lengthy process to bring up the site. "The best case was 36 hours," Lefever says.

The company replicates several gigabytes of data per day, much of it the images of cheques the company processes. That time was getting longer as the datacentre handled more traffic, so the company decided to set up a second company-owned data center to continuously replicate the first.

With the then-existing bundle of five T-1 circuits bonded into a logical 7.5Mb/s link, the backup could be online in half an hour. Much of that delay was caused by some switchovers the firm decided to keep manual as a security precaution, Lefever says. The problem, though, was that total traffic over the link had increased to an average 6-7Mb/s, with peak traffic spiking to nearly 45Mb/s. "We used the vast majority of our available bandwidth for average traffic," he says.

So the company tested devices from Expand and Peribit (now part of Juniper). Susquehanna found that for its particular mix of traffic, the Peribit gear didn't improve performance on the link, Lefever says. But the company says the Expand product improved traffic throughput enough so even spikes in traffic could be handled on the 7.5Mb/s logical link.

The set-up was tight, however, and allowed no room for growth. Lefever says over time, traffic spikes increased to highs of 80-150Mb/s, depending on the day.

"The peaks are very short, but they would cause congestion and a backlog of traffic," he says. Those peaks required an OC-3 connection, so the company bought a DS-3. The company had thought about putting in more T-1s rather than jumping to a DS-3, but it turned out the DS-3 was less expensive than multiple extra T-1s, he says.

Once the DS-3 was installed, the average traffic volume before compression was about 8Mb/s. After compression it was 4- 5Mb/s and traffic peaked at 30Mb/s. Susquehanna could have gotten by with the DS-3 and no WAN optimisation, but Lefever says he knew more application traffic was inevitable, so in mid-2005 he purchased and installed the Expand devices to give room for growth.

"Now we are looking at four or five other major data sources looking to replicate between the data centers," he says. "Without the Expand [devices] we would be looking at putting in an additional DS-3 circuit or more."

At US$5,500 (NZ$8,630) per month, that is a pricey prospect and makes the Expand optimisers attractive. "With them we can get twice, probably three times the utility out of the DS-3, and the ROI on that is just under one year," he says.

The company is considering another pair of Expand boxes to connect two other sites closer than the data centers are, so the links are less expensive, he says. "It would be closer to two to three years' ROI on the one being considered," he says.

The DS-3 failed once, but with the Expand boxes in place, daytime network traffic was maintained using just the five T-1 circuits that have remained in place for other uses, as well as backup when the DS-3 fails. That allowed business to go on unimpaired and even some replication traffic squeezed in, he says. "If the failure had been at night [when most of the replication is done] we would have fallen behind, but not so much that we couldn't catch up."

Another user of WAN acceleration gear, internet gaming company Electronic Arts, found the ROI so compelling it started a massive programme to install them on all the company's international connections, says Ruben Cortez, the company's chief network architect.

Electronic Arts wanted to consolidate its servers at fewer sites to reduce capital and administrative costs and decided it needed better-performing WAN connections so server access didn't become so slow it got in the way of doing business, he says.

Used initially on a connection between Brisbane and Sydney, the Riverbed WAN optimisers cost the company US$147,000. New file servers for the consolidation project and maintenance for a year cost US$44,000, he says. The performance increase the Riverbed gear brought about let the company put off buying more bandwidth for a year — a savings of US$78,528, he says, and the company estimates a productivity increase of US$216,000 in the first year.

That gave the project an ROI of 8.3 months, Cortez says, adding that some of the ROI is real but hard to quantify. "If I had to do it again, I'd put more emphasis on the opportunity cost of people having to wait for a file to get across. We have situations where now it's not five minutes for the next window, it's 10-15 seconds," he says.

Copyright 2018 IDG Communications. ABN 14 001 592 650. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of IDG Communications is prohibited.